Bacterial and Benthic Community Response to Inorganic and Organic Sediment Amendments

• Main Authors: Arias-Thode, Yolanda M, Rosen, Gunther, Leather, Jim
• Format: Publication
• Language: English
• Published: 01.08.2010
• Subjects: ACETATE; AMENDMENTS; AMMONIA; APATITE; AQUATIC ORGANISMS; BACTERIA; BACTERIAL COMMUNITY; BENTHONIC ZONES; CHITIN; COMMUNITIES; CONCENTRATION(CHEMISTRY); CONTAMINATION; CONTROL; CYPRINODON VARIEGATES; CYPRINODON VARIEGATUS; EOHAUSTORIUS ESTUARIUS; FIELD CONDITIONS; FOOD; GEOTEXTILES; GROWTH(PHYSIOLOGY); INORGANIC CHEMISTRY; INORGANIC COMPOUNDS; LABORATORY TESTS; LARVAL SHEEPSHEAD MINNOW; MARINE AMPHIPODS; MARINE BENTHIC COMMUNITY; MARINE POLYCHAETES; MARINE SEDIMENTS; MESOCOSMS; MICROBIOLOGY; MINNOWS; NEANTHES ARENACEODENTATA; ORGANIC CHEMISTRY; ORGANIC COMPOUNDS; ORGANOCLAY; OXYGEN; PHYSICAL AND DYNAMIC OCEANOGRAPHY; PURPLE SEA URCHINS; RESPONSE(BIOLOGY); SEDIMENTS; SHEEPSHEAD MINNOW; STRONGYLOCENTROTUS PURPURATUS; SURVIVAL(GENERAL); TEST METHODS; TOXICITY; WATER QUALITY

Experimental materials currently being investigated for use as amendments for the in situ remediation of contaminated sediments were assessed for their potential impacts on marine benthos. Laboratory toxicity tests involving several endpoints were conducted on sediments amended with apatite, organoclay, chitin, or acetate; with the polychaete Neanthes arenaceodentata, the amphipod Eohaustorius estuarius, and the sheepshead minnow Cyprinodon variegatus. Experimental geotextile mats housing apatite and organoclay were also assessed. The geotextile mats, apatite (5%), and organoclay (5%) did not result in effects on any of the test organisms. Chitin and acetate, however, repetitively induced effects on survival and/or growth. The effects associated with chitin and acetate were attributed to water quality changes in the exposure vessels (ammonia and dissolved oxygen concentration) that were a direct result of the microbial breakdown of the amendments. A sediment concentration of 0.5% chitin or acetate was subsequently determined to be free from water quality effects in control sediments. N. arenaceodentata growth was enhanced in the presence of chitin, which stimulated bacterial growth that likely provided an additional food source for the polychaete. Application of chitin (0.5%) resulted in a statistically significant reduction in N. arenaceodentata body burdens of 61, 29, and 54%, relative to unamended contaminated sediment, for Cu, Zn, and Cd, respectively. The studies suggest a probable lack of inherent toxicity of these materials on benthic or epibenthic organisms, as the effects are expected to be related to artifacts associated with laboratory tests. Assessment in field settings are needed to verify such conclusions.